Looks like Jon Tester should have taken Donald Trump both seriously and literally when the president focused his ire on him. A Trump-supporting super-PAC unveiled a new 30-second TV spot for Montana media markets calling the incumbent Democratic senator “disgraceful” for leaking anonymous and ultimately uncorroborated personal attacks on Admiral Ronny Jackson, Trump’s pick for VA Secretary. It comes two days after Trump demanded Tester’s resignation for smearing the longtime White House chief physician, who has served three presidents without public criticism:

“In Montana, we value integrity and support our president,” says the ad from the pro-Trump America First Action super PAC. “But Jon Tester spread false information about a respected Navy admiral, helping D.C. Democrats derail President Trump’s Veterans Affairs nominee.”

The spot goes on to say that Tester, one of the most vulnerable Democratic incumbents up for re-election in 2018, “betrayed our trust, our veterans and our president,” concluding that “it’s time for him to go.”

Trump has vowed to exact revenge on Tester for helping to sink Rear Adm. Ronny Jackson, who’d been Trump’s choice to run the Veterans Affairs Department. The president, eager to go after a Democratic incumbent confronting a treacherous re-election bid, has accused Tester of spreading false information about Jackson’s background in an effort to destroy the nomination.

The ad and Trump’s desire for revenge has put Tester’s re-election bid back into the national spotlight. Trump won Montana by twenty points over Hillary Clinton and the state is reliably red for presidential elections, but Tester has proven durable and other Democrats win state office in Montana as well. Steve Bullock narrowly won the gubernatorial election in 2012 with Barack Obama at the top of the Democratic ticket and won again in 2016 with Hillary Clinton there, too, with a somewhat wider 4-point edge over Greg Gianforte. At 52 years old, Bullock might be a sleeper candidate for a Democratic presidential bid.

That success might be attributed in part to the lack of national interest in these races. Tester may have upset the applecart in his haste to take out Jackson, RCP’s Caitlin Huey-Burns reports. Momentum is building for a serious challenge to Tester’s incumbency thanks to the energy that national coverage is bringing into the race:

Republicans running against Tester are following Trump’s lead, and took issue with his handling of the vetting process during a primary debate last week. “Jon Tester very conveniently brought information up against a man who was getting ready to be considered for secretary of the VA when that information seems like it was available for quite some time,” said state auditor Matt Rosendale, seen as the frontrunner in the primary.

“We have our own senator from Montana who bullied a fine man to the point he decided to pull himself out of the confirmation process. … This was wrong,” said former state Rep. Albert Olszewski. Billings Judge Russ Fagg said Tester “pre-judged” Jackson, and businessman Troy Downing argued the incumbent went public with “unsubstantiated claims.”

Republicans acknowledge that the Senate race could take multiple turns between now and November, but they see the president’s attacks as way to contrast Tester’s votes with Trump’s agenda.

“He is in a state Trump won by 20 points and he has now caught the ire of the president,” said one Montana Republican strategist. “I think this allows folks to pile on a little bit to show where he has been breaking with Trump. [Tester] put a spotlight on himself in the wrong way.”

Until now, this red-state Senate race has drawn so little attention that pollsters haven’t conducted any surveys in the state, at least none that have come to RCP’s attention. That seems odd in itself. Tester won in 2012 by four points but failed to get a majority, thanks to a Libertarian bid that drew nearly seven percent of the vote. He won his first term in the Democratic wave of 2006, barely edging out incumbent Republican Conrad Burns, 49.2/48.3. Tester doesn’t have a lot of margin for erosion, and it seems strange that national pollsters haven’t taken much of an interest in this before now.

Bet on lots of attention now, though. And don’t think Tester will be happy about it, either, especially since Tester’s strategy until now has been to emphasize how well he works across the aisle. Trump has yanked that plan out from under him, and Tester’s ability to get a plurality while being seen as an antagonist to a Republican administration has never yet been tested.